Elements of Natural Philosophy |
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Common terms and phrases
acceleration action amount angular velocity anticlastic applied attraction axes axis called centre of gravity centre of inertia circle circular co-ordinates component configuration constant corresponding cosine couple curvature curve degrees of freedom denote density described diagram displacement distance elastic elements ellipse ellipsoid elongation equal equations equilibrium external point finite fixed point fluid forces acting friction geometrical given force Hence hodograph horizontal inclined infinitely small instance inversely kinetic energy length magnitude mass matter measured moment of inertia momentum moving normal section observation P₁ P₂ parallel particle path pendulum perpendicular portion position pressure principal axes principle produce projection proportional quantity radius radius of gyration reckoned rectangular resultant right angles rigid body rotation round screw shell sides simple harmonic motion solid solid angle space spherical surface spiral square straight line strain suppose synclastic tangent torsion uniform unit vertical whole wire
Popular passages
Page 63 - Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it is compelled by force to change that state.
Page 27 - Fourier's theorem is not only one of the most beautiful results of modern analysis, but may be said to furnish an indispensable instrument in the treatment of nearly every recondite question in modern physics.
Page 65 - Change of motion is proportional to the impressed force and takes place in the direction of the straight line in which the force acts.
Page 126 - UNTIL we know thoroughly the nature of matter and the forces which produce its motions, it will be utterly impossible to submit to mathematical reasoning the exact conditions of any physical question.
Page 57 - The Component of a force in any direction, sometimes called the Effective Component in that direction, is therefore found by multiplying the magnitude of the force by the cosine of the angle between the directions of the force and the component The remaining component in this case is perpendicular to the other. It is very generally convenient to resolve forces into components parallel to three lines at right angles to each other; each such resolution being effected by multiplying by the cosine of...
Page 52 - Matter has an innate power of resisting external influences, so that every body, as far as it can, remains at rest, or moves uniformly in a straight line.
Page 231 - The substance of a homogeneous solid is called isotropic when a spherical portion of it, tested by any physical agency, exhibits no difference in quality however it is turned. Or, which amounts to the same, a cubical portion cut from any position in an isotropic body exhibits the same qualities relatively to each pair of parallel faces. Or two equal and similar portions cut from any positions in the body, not subject to the condition of parallelism, are undistinguishable from one another. A substance...
Page 107 - ... the residual phenomenon as to be able to detect its cause. It is here, perhaps, that in the present state of science we may most reasonably look for extensions of our knowledge ; at all events we are warranted by the recent history of Natural Philosophy in so doing. Thus, to take only a very few T.
Page 72 - ... its application to mechanics*. The actio agentis, as he defines it, which is evidently equivalent to the product of the effective component of the force, into the velocity of the point on which it acts, is simply, in modern English phraseology, the rate at which the agent works. The subject for measurement here is precisely the same as that for which Watt, Horse- a hundred years later, introduced the practical unit of a "Horsepower...
Page 50 - We cannot, of course, give a definition of Matter which will satisfy the metaphysician ; but the naturalist may be content to know matter as that which can be perceived by the senses, or as that which can be acted upon by, or can exert, force.